Process of deinking



Patented July 14, 1925.

RICHARD W. G. STUTZKE, OF CHICAGO, ILLINOIS.

PROCESS or DEINKING.

, No Drawing.

To all whom it may concern:

Be it known that I, RICHARD W. G. STUTZKE, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Processesof Deinking, of which the following is a specification.

This invention relates to a new and improved method of de-inking paper, and more particularly to a means and method for removing printing ink from waste newsprint print paper.

and other paper, whereby such waste may be again used in paper making.

In printing establishments such as newspaper printing rooms there is a very considerable Waste of paper, due to a variety of causes, such as misprinting or tearing of the paper. There is further considerable wastage due to printing of excess copies and of returns from the news stands. There is also becoming available, an increasing quantlty of used and old newspapers collected by junkmen and trash collectors.

Due to the increasing cost of paper making material, and consequently of paper, the utilization of these waste papers by again turning them into usable newsprint is becoming of considerable importance to the trade. It has heretofore been impossible to de-ink the waste newsprint sufficiently completely to permit its use in making new news- This waste has therefore been used in making heavy wrapping paper, or cheap grades of board.

With papers made with a rag base, it has been possible to de-ink by the use of caustic soda or similar materials, but these cannot be successfullv used with wood pulp paper since such de-inking agents attac the wood fibre and have a deleterious eifect upon it.

Ordinary newsprint contains a major portion 'of ground wood pulp with a smaller portion, of the more expensive sulphite pulp. This latter is added to give suflicient strength to the paper. Where properly de-inked, waste paper is available and can be-supplied in pulp form for paper making the quantity of sulphite stock necessary can be materially ing the material from the present sources of supply of paper material are eliminated.

Application filed August 8, 1924. fierial No. $31,000.

It is an object of the present invention to provide a new. and improved means and method for de-inking waste paper.

It is a further object to provide a means and method of this character, using agents having no deleterious effect upon wood fibre and consequently particularly adapted for use with news rint paper or the like.

' Other and filrther objects will appear as the description proceeds.

I have found that the paper may be effectively de-inked by a itatlon in a solution of a soluble silicate, such for example as sodium silicate, or water glass. The process may include with the soluble silicate, a reagent adapted to free the silicic acid from the silicate. As typical of such reagents hydrochloric acid and sodium bicarbonate may be mentioned.

A satisfactory solution has been found to consist of equal parts of a 40 B. solution of The use of the rea ent consists in agitating the material to be e-inked in the solution, which may be either heated or cold. A somewhat weaker solution may be used with heat, but the cold solution will de-ink the material" in a satisfactory manner. After the de-inking has taken place, the material is rinsed or washed and then may be used in any desired manner as an addition to fresh pulp for use in paper making.

I claim:

1. The method of de-inking paper or the like which comprises agitating the material in a solution of sodium silicate, and a reagent adapted to liberate silicic acid from the silicate and to combine with the caustic freed by the reaction, and washing out the solution from the material.

2. The method of de-inking paper or the likecwhich com rises agitating the material in a solution of sodium silicate and'sodium bicarbonate, and washing out the solution from the material.

Signed at Chicago, Illinois, this 6th day of August, 1924.

RICHARD W. G. STUTZKE. 

